1) Field of the Invention
The present invention relates to an apparatus and a method of detecting whether or not a subject of which biometric information should be acquired is a living body in an authenticating apparatus for employing biometric information such as, for example, a fingerprint, a palm print, and a blood vessel pattern, thereby to make personal authentication.
Also, the present invention relates to an authenticating apparatus for employing biometric information such as, for example, a fingerprint, a palm print, and a blood vessel pattern, thereby to make personal authentication, and more particularly to an authenticating apparatus having a living-body detecting function for detecting whether or not a subject, being an object of biometric information acquisition, is a living body in acquiring biometric information from a person to be authenticated.
2) Description of the Related Art
Small-sized information appliances such as a mobile telephone and a PDA (Personal Digital Assistant) have been allowed to be connected to a network in some cases, or to file a large capacity of personal information etc. in some cases, accompanied by their highly-developed functions of recent years, and a demand for improving a security performance in these appliances have been augmented exceedingly.
So as to insure a security in such appliances, it can be thought to employ personal authentication by means of a password or an ID (Identification) card etc. which haven been widely used hitherto. The password or the ID card, however, has a high risk of being stolen, so realization of personal authentication with a higher reliability (authenticating that an appliance's user is a pre-registered user) has been strongly requested. For such a request, it is believed that the personal authentication by means of biometric information has a high reliability and can respond to the foregoing request. In particular, its convenience is also high in a case of employing a fingerprint as biometric information.
In a case of employing the fingerprint as biometric information, thereby to make personal authentication, the fingerprint (a pattern which is comprised of ridges, which can touch an obtaining plane of a fingerprint sensor, and valleys, which do not touch the identical obtaining plane) is obtained as image information from a finger of a person to be authenticated with a capacitance type fingerprint sensor or an optical fingerprint sensor. And, characteristic information (for example, position information of bifurcations or end-points) is extracted from the foreground (for example, ridge images) of its fingerprint image to compare the extracted characteristic information with registered characteristic information of a person to be authenticated, which was pre-registered, and thereby to make a determination as to whether or not the person to be authenticated is a person who has performed the registration of the registered characteristic information, that is, personal authentication.
By the way, in a system in which the fingerprint is employed to make personal authentication as described above, unjust utilization employing a forged fingerprint has been pointed out as one of the problems upon making personal authentication having a high reliability. That is, in a system of employing the fingerprint, there is the possibility that a finger having the forged fingerprint is artificially fabricated to make successful impersonation employing its artificial finger, and the unjust utilization by an act of its successful impersonation might incur degradation in a reliability of the system.
In a case where silicon or rubber was employed as a material of the artificial finger, it is impossible to make the unjust utilization as described above, because these materials are impervious to electricity, so the capacitance type fingerprint sensor has no operation of obtaining the fingerprint images from an artificial finger made of silicon or an artificial finger made of rubber. Also, the optical fingerprint sensor as well is not able to obtain the fingerprint image basically from the artificial finger made of silicon or the artificial finger made of rubber.
However, it has been pointed out that employing gummi (which is obtained by gelling aqueous solution of gelatin), of which the composition is extremely akin to that of the integument of a human being, as a material of the artificial finger allows the capacitance type fingerprint sensor or the optical fingerprint sensor to obtain the fingerprint image from the artificial finger made of gummi because the gummi is pervious to electricity, thus enabling the unjust utilization by an action of the successful impersonation.
The technologies for excluding the unjust utilization by the forged fingerprint were disclosed, for example, in Japanese Patent Laid-open (Kokai) No. 2000-123143, Japanese Patent Laid-open (Kokai) No. HEI 10-302047, Japanese Patent Laid-open (Kokai) No. HEI 2000-194848, Japanese Patent Laid-open (Kokai) No. 2000-172833, etc.
However, in the technologies disclosed in Japanese Patent Laid-open (Kokai) No. 2000-123143 or Japanese Patent Laid-open (Kokai) No. HEI 10-302047, it is determined whether or not the subject is a living body by means of an electric current value, an electrostatic capacity, an electric resistance, etc. of the subject, so it is impossible to exclude the forged fingerprint of the artificial finger made of gummi which is pervious to electricity as described above. Also, the forged fingerprint is determined by whether or not the capacitance type sensor makes a reaction in the technology disclosed in Japanese Patent Laid-open (Kokai) No. HEI 10-370295, and the forged fingerprint is determined by a frequency characteristic of impedance, being an electric characteristic, in the technology disclosed in Japanese Patent Laid-open (Kokai) No. 2000-172833, so it is impossible for either of these technologies to exclude the forged fingerprint of the artificial finger made of gummi which is pervious to electricity.
The present invention has been originated in consideration of such problems, and a first object thereof is to provide a living-body detecting apparatus and method allowing a detection as to whether or not the subject is a living body to be made securely, thus making it possible to securely identify a non-living body such as, for example, the artificial finger made of gummi.
Also, the present invention has a second object of providing an authenticating apparatus having a living-body detecting function which allows a detection as to whether or not the subject, being an object of biometric information acquisition, is a living body to be made securely in acquiring biometric information from a person to be authenticated for purposes of employing biometric information such as, for example, a fingerprint and a palm print, thereby to make personal authentication, securely identifies, for example, the artificial finger made of gummi, securely excludes the unjust utilization by an action of successful impersonation employing the forged fingerprint, and realizes personal authentication having a higher reliability.